Environmental Impact The change of species over time

Environmental Impact The change of species over time

Evolution – THE FACTS • It is the change of a species over a period of time. • It is NOT theory that we evolved from primates (monkeys). • Charles Darwin was the first scientist to suggest that because of environmental factors a species can change over time. • He never stated that humans evolved from apes.

Environmental Impact • Over long time periods, the environment impacts a species’ ability to survive. • Nonliving influences include temperature, rainfall, fire, elevation, volcanic eruptions, periodic flooding, and pollution. • Living influences include availability of food, predators, and the number of species living in an area affect a species’ survival.

Darwin and Wallace • They are scientists who explained evolution – over time environmental factors can change the genetics of a species. • Natural selection – organisms best adapted to their environment have a higher rate of survival and reproduction than organisms less well adapted. – This is also known as survival of the fittest

Natural Selection • Species that can adapt to their environment survive, those who cannot adapt die. • As a result, the genes that disabled a species from living in a particular environment are eliminated from the gene pool.

Mutation • A process in which DNA changes to form new alleles. • Mutations occur all the time. • Each one of us has some sort of mutation in our DNA. • Mutations are not bad. • When you cross a donkey with a horse, a mutation occurs. Do you know what this mutation creates?

Selective Breeding • Selective breeding involves human choice in the traits desired in offspring. • It differs from natural selection because it is not natural. Humans are selecting the species based on certain traits or characteristics. • The different breeds of dogs is an example of selective breeding.

Adaptive Radiation • Adaptive radiation occurs when one ancestral species produces several new species over time.

Extinction • Extinction – the end of a species. • It can occur for many reasons including, destruction of habitat, extreme environmental changes, poaching/over hunting, or the introduction of a new species.